Piston-type fastening tool



Dec. 12, 1967 w. E. OSBORNE PISTON-TYPE FASTENING TOOL Filed March 30, 1966 INVENTOR. -W/LL/AM E OSBORNE A TTO/PNE V United States Patent 3,357,617 PISTON-TYPE FASTENING TOOL William E. Osborne, East Haven, Conn.,. assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Mar. 30, 1966, Ser. No. 538,657 6 Claims. (Cl. 227-) This invention relates generally to power-actuated tools for driving fasteners into masonry, steel, concrete, or the like, and more particularly to such tools which utilize a piston to drive the fastener.

Two problems to be considered in the design of pistontype fastening tools are the return of the piston to the breech end of the tool after each shot and providing means for loading a fastener into the tool. Many piston tools have elaborate systems for returning the piston to the breech end of the tool after each shot. Some systems utilize the pressure of the gases generated by the explosion of the propellant, while other systems rely simply upon the movement of the fastener being inserted in the muzzle end of the barrel to move the piston rearwardly in the tool. These systems suffer from the disadvantage of being either too complex and, therefore, costly to manufacture and maintain or from the fact that the operation of loading the tool and returning the piston is an awkward maneuver for the operator and, therefore, time consuming and ineffcient.

It is, therefore, an object of the present invention to provide a simplified system for loading a fastener and returning the piston to the breech end of the tool.

More specifically it is an object of this invention to provide a piston-type power-actuated tool wherein a.

loading port is opened and the piston returned to the breech end of the tool in one motion of the operator.

These and other objects of the invention will become more apparent by reference to the following description of a preferred embodiment and to the accompanying drawings in which:

FIGURE 1 is a top plan view of the forward portion of a tool embodying the principles of the present invention,

FIGURE 2 is a transverse sectional view taken along the lines 22 of FIGURE 1 showing the loading port open,

FIGURE 3 is a view similar to FIGURE 2, but showing the loading port closed; and

FIGURE 4 is a sectional view taken along the lines 4-4 of FIGURE 2.

Referring to the drawings, a tool constructed in accordance with this invention may include a barrel member 2 having an opening forming a loading port 4 near the forward end thereof. The loading port 4 is positioned at the top of the barrel member 2. A piston member 6 is mounted for reciprocal axial movement within the barrel member 2 and includes a head portion 8 supported by the internal surface of the barrel member 2 and a reduced shank portion 10 extending forwardly from the head portion 8 toward the forward end of the tool. The barrel member 2 includes a reduced bore 12 forwardly of the loading port 4 which forms an internal shoulder 14 in the interior of the barrel member 2. The reduced bore 12 is substantially the same diameter as the diameter of the shank portion 10 of piston member 6.

It is to be understood that a suitable breech structure is mounted at the rearward end of the barrel member 2 (to the right as shown in FIGURES 1-3) to provide a suitable trigger mechanism and explosion chamber for generating explosive gases from a suitable power source such as a powder containing cartridge, liquid propellant or caseless ammunition to drive the piston member 6. As

3,35 7,6 l 7 Patented Dec. 12, 1 967 any conventional breech structure may be used, and since the details of such breech structure are not necessary for an understanding of this invention, such structure has not been shown in the drawings.

A loading tray 16 is mounted within the barrel member 2 diametrically opposite the loading port 4 with its forward face 18 abutting the shoulder 14 and extends rearwardly in the tool a distance greater than the length of the loading port 4. The loading tray 16 is secured to the barrel member 2 by any suitable meanssuch as screws 20.

A slide member 22 is mounted within the barrel member 2 above the loading tray 16 and includes a hand grip 24 projecting upwardly through the loading port 4. As can be seen particularly in FIGURE 4, the internal surfaces 26 and 28 of the loading tray 16 and slide member 22 respectively are semi-circular in cross section and have a diameter substantially equal to the diameter of the shank portion 10 of the piston member 6. I

The length of the slide member 22 is substantially the same as the length of the loading tray 16 which is long enough to close the loading port 4 when the slide member 22 is in its forward position as shown in FIGURE 2. The length of the slide member 22 should also be enough so that when it is positioned rearwardly in the tool and the loading port 4 is fully open, its rearward face 36 contacts the forward face 38 of the head portion 8 of piston member 6 when the piston member is in its firing position at the breech end of the tool.

A sliding sleeve member 30 is disposed about the barrel member 2 and is positioned rearwardly of hand grip 24 of the slide member 22. A spring member 32 abuts the rearward face 34 of the sleeve member 30 and biases the sleeve member 30 toward the forward end of the tool.

When the slide member 22 is moved by the operator to its rearward most position wherein the grip 24 abuts surface 40 defining the rearward end of the loading port 4 and the loading port 4 is open,a fastener 42 may be inserted into the tool in the position shown in FIGURE 2. Such fastener 42 may include an enlarged head portion 44, a reduced shank portion 46 terminating in a tapering tip portion, and a washer 48 or other member adjacent the forward end thereof. A detent 50 is provided in the bottom portion of the loading tray 16 in a position to be just forward of the head portion 44- of the fastener 42 when the fastener 42 is inserted into the tool. The detent 50 may include a small ball member 52 mounted in a bore 54 in the wall of the loading tray 16 and biased toward the center of the tool by a suitable spring member 56.

After the fastener 42 has been inserted in the tool in proper position, the operator may release the slide member 22 whereupon the spring 32 acting upon the sleeve member 30 will move both the sleeve member 30 and slide member 22 forwardly relative to the barrel member 2 until the forward face 58 of the slide member 22 contacts surface 60 which defines the forward end of the loading port 4 and is coincident with the shoulder 14. The detent 50' prevents the fastener 42 from being moved forwardly in the tool out of its proper firing position when the slide member 22 passes over the head portion 44 and washer 48.

After the driving operation, the piston member 6 will have moved forwardly relative to the barrel member 2 into a position wherein the forward face 38 of the head portion 8 is against or spaced slightly from the rearward face 36 of the slide member 22. Accordingly, when the operator grasps the grip 24 and moves the slide member 22 rearwardly within the barrel member 2 to open the loading port 4, its rearward face 36 will engage the forward face 38 of the head portion 8 of piston memher 6 and move the piston member 6 rearwardly in the tool into its firing position.

The above-described arrangement provides an efiicient system foruse in a power-actuated tool of the piston type wherein one motion of the operator in moving the slide member 22 from its forward to rearward position opens the loading port 4 and returns the piston member 6 to its firing position. Moreover, with this arrangement, the forward portion of the shank portion 10 of the piston member 6 as well as the fastener 42 are fully supported when the loading port 4 is closed.

What is claimed is:

1. In a power-actuated fastening tool, a barrel member having a loading port, a piston member reciprocal in said barrel member between a breech position and a driven position, slidable means in said barrel movable between a first position closing said loading port and a second position wherein said loading port is open, said means being operable upon movement from said first position to said second position to engage said piston when said piston is in said driven position and return said piston to said breech position.

2. The tool as set forth in claim 1 further including biasing means urging said slidable means into its first position.

3. The tool of claim 2 further including a loading tray positioned within said barrel member diametrically opposite from said loading port, and wherein said piston includes a head portion slidably supported within said barrel member and a reduced shank portion extending forwardly from said head portion, said slidable means comprises a member slidably disposed within said barrel member and having an inner surface complementary to the inner surface of said loading tray with each of said inner surfaces supporting said shank portion.

4. The tool of claim 3 wherein said biasing means includes an outer sleeve member slidably disposed about said barrel member and spring means urging said outer sleeve member toward the forward end of said tool, and said slidable means includes a hand grip projection extending upwardly through said loading port and into a position to be abutted by said slidable sleeve means to be urged into its first position.

5. The tool of claim 4 further including detent means positioned in said loading tray forwardly of the end of said shank portion when said piston is in its breech position and biased into a position extending into the interior of the tool.

6. The tool of claim 5 wherein said detent means comprises ball means projecting into the interior of said tool and spring means biasing said ball means.

References Cited UNITED STATES PATENTS 2,970,314 2/1961 Temple et al 2278 GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. IN A POWER-ACTUATED FASTENING TOOL, A BARREL MEMBER HAVING A LOADING PORT, A PISTON MEMBER RECIPROCAL IN SAID BARREL MEMBER BETWEEN A BREECH POSITION AND A DRIVEN POSITION, SLIDABLE MEANS IN SAID BARREL MOVABLE BETWEEN A FIRST POSITION CLOSING SAID LOADING PORT AND A SECOND POSITION WHEREIN SAID LOADING PORT IS OPEN, SAID MEANS BEING OPERABLE UPON MOVEMENT FROM SAID FIRST POSITION TO SAID SECOND POSITION TO ENGAGE SAID PISTON WHEN SAID PISTON IS IN SAID DRIVEN POSITION AND RETURN SAID PISTON TO SAID BREECH POSITION. 